Galaxy collisions as a mechanism of ultra diffuse galaxy (UDG) formation

Understand

We suggest a possible mechanism of ultra diffuse galaxy formation: the UDGs may occur as a result of a central collision of galaxies.

• If the galaxies are young and contain a lot of gas, the collision may kick all the gas off the systems and thus strongly suppress any further star formation.
• As a result, the galaxies now have a very low surface brightness and other properties typical of the ultra diffuse galaxies.
• We use the Coma cluster (where numerous UDGs were recently discovered) to test the efficiency of the process.